1. Electrolytes
Electrolytes are solutes that dissolve in water. The polarity of water breaks them apart to form ions. The resulting solution will conduct electricity. (Water alone does not conduct electricity.)
Strong electrolytes dissociate completely as they dissolve while weak electrolytes separate into a relatively few ions
The process of forming ions while dissolving is called dissociation
Electrolytes (ions) are necessary for manyphysiological processes in the body (ex: muscle contractions and nerve impulses)
Na+ and K+ are examples of electrolytes required by the nervous system in order to conduct nerve impulses

2. Electrolytes, Acids and Bases
There are three types of substances that behave as electrolytes:
acids (ex: HCl) more H+ ions are created than OH- ions when acids dissociate
Ex: CH3COOH (vinegar) CH3COO- + H+ (in water)
bases (ex: NaOH) more OH- ions are created than H+ ions when bases dissociate
Ex: NaOH + H2O Na+ + OH- (in water)
salts (ex: NaCl) positive and negative ions are formed when salts dissociate, but neither are H+ or OH-
Ex: NaCl Na+ + Cl- (in water)
Substances that create an equal number of H+ and OH- ions when they dissolve (dissociate) in water are neutral. Water itself is an example:
H2O H+ + OH H3O+ + OH-

3. Acids and Bases
The pH scale is used to measure the concentration of H+ ions compared to OH- ions that form when a substance dissociates in water
H+ ions > OH- ions = acid, pH < 7
H+ ions < OH- ions = base/alkaline, pH > 7
H+ ions = OH- ions = pH of 7, neutral

4. Acids and Bases
The pH scale is logarithmic. Each decreasing value represents a 10 fold increase in H+ ions.
Ex: vinegar forms about 10 times more H+ ions in water than tomatoes do and about 10,000 times more H+ ions in water than blood does.
How does the concentration of H+ ions formed in water for blood compare to that of saliva? What about blood compared to bleach?

5. Acids and Bases NaOH + HCl NaCl + H2O
Strong acids and bases are dangerous because ions react easily with other compounds. The higher the ion concentration, the greater the “pressure” to react and so strong acids and bases undergo chemical reactions that destroy other compounds causing chemical burns to human tissues (a “burn” just means chemical damage – similarly really hot surfaces and fire can cause chemical damage to tissues as well)
pH affects the rate of chemical reactions – so the body must maintain a fairly stable pH in order to operate properly (this is one example of homeostasis)
Buffers are used to help maintain a stable pH. A buffer is a substance that has a highly stable pH when dissolved in water. If you add acid or base to a buffered solution, its pH will not change significantly.
When acids and bases are mixed together, they form salts:
NaOH + HCl NaCl + H2O
Salt